[AMDGPU] Check vector sizes for physical register constraints in inli…

…ne asm (llvm#109955) For register constraints that require specific register ranges, the width of the range should match the type of the associated parameter/return value. With this PR, we error out when that is not the case. Previously, these cases would hit assertions or llvm_unreachables. The handling of register constraints that require only a single register remains more lenient to allow narrower non-vector types for the associated IR values. For example, constraining an i16 or i8 value to a 32-bit register is still allowed. Fixes llvm#101190. --------- Co-authored-by: Matt Arsenault <arsenm2@gmail.com>
durga4github · Oct 1, 2024 · 3ba4092 · 3ba4092
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diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -15510,6 +15510,10 @@ SITargetLowering::getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI_,
         Failed |= !RegName.consume_back("]");
         if (!Failed) {
           uint32_t Width = (End - Idx + 1) * 32;
+          // Prohibit constraints for register ranges with a width that does not
+          // match the required type.
+          if (VT.SimpleTy != MVT::Other && Width != VT.getSizeInBits())
+            return std::pair(0U, nullptr);
           MCRegister Reg = RC->getRegister(Idx);
           if (SIRegisterInfo::isVGPRClass(RC))
             RC = TRI->getVGPRClassForBitWidth(Width);
@@ -15523,6 +15527,9 @@ SITargetLowering::getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI_,
           }
         }
       } else {
+        // Check for lossy scalar/vector conversions.
+        if (VT.isVector() && VT.getSizeInBits() != 32)
+          return std::pair(0U, nullptr);
         bool Failed = RegName.getAsInteger(10, Idx);
         if (!Failed && Idx < RC->getNumRegs())
           return std::pair(RC->getRegister(Idx), RC);

diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/inline-asm-mismatched-size.ll b/llvm/test/CodeGen/AMDGPU/GlobalISel/inline-asm-mismatched-size.ll
@@ -3,11 +3,14 @@
 ; RUN: FileCheck -check-prefix=ERR %s < %t
 
 ; ERR: remark: <unknown>:0:0: unable to translate instruction: call: '  %sgpr = call <4 x i32> asm sideeffect "; def $0", "={s[8:12]}"()' (in function: return_type_is_too_big_vector)
+; ERR: remark: <unknown>:0:0: unable to translate instruction: call: '  %sgpr = call <4 x i32> asm sideeffect "; def $0", "={s[8:10]}"()' (in function: return_type_is_too_small_vector)
 ; ERR: remark: <unknown>:0:0: unable to translate instruction: call: '  %reg = call i64 asm sideeffect "; def $0", "={v8}"()' (in function: return_type_is_too_big_scalar)
+; ERR: remark: <unknown>:0:0: unable to translate instruction: call: '  %reg = call i32 asm sideeffect "; def $0", "={v[8:9]}"()' (in function: return_type_is_too_small_scalar)
 ; ERR: remark: <unknown>:0:0: unable to translate instruction: call: '  %reg = call ptr addrspace(1) asm sideeffect "; def $0", "={v8}"()' (in function: return_type_is_too_big_pointer)
 ; ERR: remark: <unknown>:0:0: unable to translate instruction: call: '  %reg = call ptr addrspace(3) asm sideeffect "; def $0", "={v[8:9]}"()' (in function: return_type_is_too_small_pointer)
 ; ERR: remark: <unknown>:0:0: unable to translate instruction: call: '  call void asm sideeffect "; use $0", "{v[0:9]}"(<8 x i32> %arg)' (in function: use_vector_too_big)
 ; ERR: remark: <unknown>:0:0: unable to translate instruction: call: '  call void asm sideeffect "; use $0", "{v0}"(i64 %arg)' (in function: use_scalar_too_small)
+; ERR: remark: <unknown>:0:0: unable to translate instruction: call: '  call void asm sideeffect "; use $0", "{v[0:1]}"(i32 %arg)' (in function: use_scalar_too_big)
 ; ERR: remark: <unknown>:0:0: unable to translate instruction: call: '  call void asm sideeffect "; use $0", "{v0}"(ptr addrspace(1) %arg)' (in function: use_pointer_too_small)
 ; ERR: remark: <unknown>:0:0: unable to translate instruction: call: '  call void asm sideeffect "; use $0", "{v[0:1]}"(ptr addrspace(3) %arg)' (in function: use_pointer_too_big)
 
@@ -24,18 +27,25 @@ define amdgpu_kernel void @return_type_is_too_big_vector() {
   ; CHECK-NEXT:   [[COPY:%[0-9]+]]:_(p4) = COPY $sgpr2_sgpr3
   ; CHECK-NEXT: {{  $}}
   ; CHECK-NEXT: bb.1 (%ir-block.0):
-  ; CHECK-NEXT:   INLINEASM &"; def $0", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $sgpr8_sgpr9_sgpr10_sgpr11_sgpr12
   %sgpr = call <4 x i32> asm sideeffect "; def $0", "={s[8:12]}" ()
   call void asm sideeffect "; use $0", "s"(<4 x i32> %sgpr) #0
   ret void
 }
 
-; FIXME: This is crashing in the DAG
-; define amdgpu_kernel void @return_type_is_too_small_vector() {
-;   %sgpr = call <4 x i32> asm sideeffect "; def $0", "={s[8:10]}" ()
-;   call void asm sideeffect "; use $0", "s"(<4 x i32> %sgpr) #0
-;   ret void
-; }
+; This is broken because it requests 3 32-bit sgprs to handle a 4xi32 result.
+define amdgpu_kernel void @return_type_is_too_small_vector() {
+  ; CHECK-LABEL: name: return_type_is_too_small_vector
+  ; CHECK: bb.0:
+  ; CHECK-NEXT:   successors: %bb.1(0x80000000)
+  ; CHECK-NEXT:   liveins: $sgpr2_sgpr3
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:_(p4) = COPY $sgpr2_sgpr3
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.1 (%ir-block.0):
+  %sgpr = call <4 x i32> asm sideeffect "; def $0", "={s[8:10]}" ()
+  call void asm sideeffect "; use $0", "s"(<4 x i32> %sgpr) #0
+  ret void
+}
 
 define i64 @return_type_is_too_big_scalar() {
   ; CHECK-LABEL: name: return_type_is_too_big_scalar
@@ -50,12 +60,10 @@ define i64 @return_type_is_too_big_scalar() {
 
 define i32 @return_type_is_too_small_scalar() {
   ; CHECK-LABEL: name: return_type_is_too_small_scalar
-  ; CHECK: bb.1 (%ir-block.0):
-  ; CHECK-NEXT:   INLINEASM &"; def $0", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $vgpr8_vgpr9
-  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:_(s64) = COPY $vgpr8_vgpr9
-  ; CHECK-NEXT:   [[TRUNC:%[0-9]+]]:_(s32) = G_TRUNC [[COPY]](s64)
-  ; CHECK-NEXT:   $vgpr0 = COPY [[TRUNC]](s32)
-  ; CHECK-NEXT:   SI_RETURN implicit $vgpr0
+  ; CHECK: bb.0:
+  ; CHECK-NEXT:   successors: %bb.1(0x80000000)
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.1 (%ir-block.0):
   %reg = call i32 asm sideeffect "; def $0", "={v[8:9]}" ()
   ret i32 %reg
 }
@@ -77,7 +85,6 @@ define ptr addrspace(3) @return_type_is_too_small_pointer() {
   ; CHECK-NEXT:   successors: %bb.1(0x80000000)
   ; CHECK-NEXT: {{  $}}
   ; CHECK-NEXT: bb.1 (%ir-block.0):
-  ; CHECK-NEXT:   INLINEASM &"; def $0", 1 /* sideeffect attdialect */, 10 /* regdef */, implicit-def $vgpr8_vgpr9
   %reg = call ptr addrspace(3) asm sideeffect "; def $0", "={v[8:9]}" ()
   ret ptr addrspace(3) %reg
 }
@@ -141,14 +148,13 @@ define void @use_scalar_too_small(i64 %arg) {
 
 define void @use_scalar_too_big(i32 %arg) {
   ; CHECK-LABEL: name: use_scalar_too_big
-  ; CHECK: bb.1 (%ir-block.0):
+  ; CHECK: bb.0:
+  ; CHECK-NEXT:   successors: %bb.1(0x80000000)
   ; CHECK-NEXT:   liveins: $vgpr0
   ; CHECK-NEXT: {{  $}}
   ; CHECK-NEXT:   [[COPY:%[0-9]+]]:_(s32) = COPY $vgpr0
-  ; CHECK-NEXT:   [[ANYEXT:%[0-9]+]]:_(s64) = G_ANYEXT [[COPY]](s32)
-  ; CHECK-NEXT:   $vgpr0_vgpr1 = COPY [[ANYEXT]](s64)
-  ; CHECK-NEXT:   INLINEASM &"; use $0", 1 /* sideeffect attdialect */, 9 /* reguse */, $vgpr0_vgpr1
-  ; CHECK-NEXT:   SI_RETURN
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.1 (%ir-block.0):
   call void asm sideeffect "; use $0", "{v[0:1]}"(i32 %arg)
   ret void
 }

diff --git a/llvm/test/CodeGen/AMDGPU/inlineasm-mismatched-size-error.ll b/llvm/test/CodeGen/AMDGPU/inlineasm-mismatched-size-error.ll
@@ -0,0 +1,104 @@
+; RUN: not llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -filetype=null %s 2>&1 | FileCheck -check-prefix=ERR %s
+
+; Diagnose register constraints that are not wide enough.
+
+; ERR: error: couldn't allocate output register for constraint '{v[8:15]}'
+define <9 x i32> @inline_asm_9xi32_in_8v_def() {
+  %asm = call <9 x i32> asm sideeffect "; def $0", "={v[8:15]}"()
+  ret <9 x i32> %asm
+}
+
+; ERR: error: couldn't allocate input reg for constraint '{v[8:15]}'
+define void @inline_asm_9xi32_in_8v_use(<9 x i32> %val) {
+  call void asm sideeffect "; use $0", "{v[8:15]}"(<9 x i32> %val)
+  ret void
+}
+
+; ERR: error: couldn't allocate output register for constraint '{s[8:15]}'
+define <9 x i32> @inline_asm_9xi32_in_8s_def() {
+  %asm = call <9 x i32> asm sideeffect "; def $0", "={s[8:15]}"()
+  ret <9 x i32> %asm
+}
+
+
+; Diagnose register constraints that are too wide.
+
+; ERR: error: couldn't allocate output register for constraint '{v[8:16]}'
+define <8 x i32> @inline_asm_8xi32_in_9v_def() {
+  %asm = call <8 x i32> asm sideeffect "; def $0", "={v[8:16]}"()
+  ret <8 x i32> %asm
+}
+
+; ERR: error: couldn't allocate input reg for constraint '{v[8:16]}'
+define void @inline_asm_8xi32_in_9v_use(<8 x i32> %val) {
+  call void asm sideeffect "; use $0", "{v[8:16]}"(<8 x i32> %val)
+  ret void
+}
+
+; ERR: error: couldn't allocate output register for constraint '{s[8:16]}'
+define <8 x i32> @inline_asm_8xi32_in_9s_def() {
+  %asm = call <8 x i32> asm sideeffect "; def $0", "={s[8:16]}"()
+  ret <8 x i32> %asm
+}
+
+
+; Diagnose mismatched scalars with register ranges
+
+; ERR: error: couldn't allocate output register for constraint '{s[4:5]}'
+define void @inline_asm_scalar_read_too_wide() {
+  %asm = call i32 asm sideeffect "; def $0 ", "={s[4:5]}"()
+  ret void
+}
+
+; ERR: error: couldn't allocate output register for constraint '{s[4:4]}'
+define void @inline_asm_scalar_read_too_narrow() {
+  %asm = call i64 asm sideeffect "; def $0 ", "={s[4:4]}"()
+  ret void
+}
+
+; Single registers for vector types that are too wide or too narrow should be
+; diagnosed.
+
+; ERR: error: couldn't allocate input reg for constraint '{v8}'
+define void @inline_asm_4xi32_in_v_use(<4 x i32> %val) {
+  call void asm sideeffect "; use $0", "{v8}"(<4 x i32> %val)
+  ret void
+}
+
+; ERR: error: couldn't allocate output register for constraint '{v8}'
+define <4 x i32> @inline_asm_4xi32_in_v_def() {
+  %asm = call <4 x i32> asm sideeffect "; def $0", "={v8}"()
+  ret <4 x i32> %asm
+}
+
+; ERR: error: couldn't allocate output register for constraint '{s8}'
+define <4 x i32> @inline_asm_4xi32_in_s_def() {
+  %asm = call <4 x i32> asm sideeffect "; def $0", "={s8}"()
+  ret <4 x i32> %asm
+}
+
+; ERR: error: couldn't allocate input reg for constraint '{v8}'
+; ERR: error: couldn't allocate input reg for constraint 'v'
+define void @inline_asm_2xi8_in_v_use(<2 x i8> %val) {
+  call void asm sideeffect "; use $0", "{v8}"(<2 x i8> %val)
+  call void asm sideeffect "; use $0", "v"(<2 x i8> %val)
+  ret void
+}
+
+; ERR: error: couldn't allocate output register for constraint '{v8}'
+; ERR: error: couldn't allocate output register for constraint 'v'
+define <2 x i8> @inline_asm_2xi8_in_v_def() {
+  %phys = call <2 x i8> asm sideeffect "; def $0", "={v8}"()
+  %virt = call <2 x i8> asm sideeffect "; def $0", "=v"()
+  %r = and <2 x i8> %phys, %virt
+  ret <2 x i8> %r
+}
+
+; ERR: error: couldn't allocate output register for constraint '{s8}'
+; ERR: error: couldn't allocate output register for constraint 's'
+define <2 x i8> @inline_asm_2xi8_in_s_def() {
+  %phys = call <2 x i8> asm sideeffect "; def $0", "={s8}"()
+  %virt = call <2 x i8> asm sideeffect "; def $0", "=s"()
+  %r = and <2 x i8> %phys, %virt
+  ret <2 x i8> %r
+}
diff --git a/llvm/test/CodeGen/AMDGPU/inlineasm-mismatched-size.ll b/llvm/test/CodeGen/AMDGPU/inlineasm-mismatched-size.ll
@@ -0,0 +1,162 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 < %s | FileCheck -check-prefix=CHECK %s
+
+; Allow single registers that are too wide for the IR type:
+
+define i16 @inline_asm_i16_in_v_def() {
+; CHECK-LABEL: inline_asm_i16_in_v_def:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; def v8
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; def v0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    v_and_b32_e32 v0, v8, v0
+; CHECK-NEXT:    s_setpc_b64 s[30:31]
+  %phys = call i16 asm sideeffect "; def $0", "={v8}"()
+  %virt = call i16 asm sideeffect "; def $0", "=v"()
+  %r = and i16 %phys, %virt
+  ret i16 %r
+}
+
+define void @inline_asm_i16_in_v_use(i16 %val) {
+; CHECK-LABEL: inline_asm_i16_in_v_use:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; CHECK-NEXT:    v_and_b32_e32 v8, 0xffff, v0
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; use v8
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; use v8
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    s_setpc_b64 s[30:31]
+  call void asm sideeffect "; use $0", "{v8}"(i16 %val)
+  call void asm sideeffect "; use $0", "v"(i16 %val)
+  ret void
+}
+
+define i16 @inline_asm_i16_in_s_def() {
+; CHECK-LABEL: inline_asm_i16_in_s_def:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; def s8
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; def s4
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    s_and_b32 s4, s8, s4
+; CHECK-NEXT:    v_mov_b32_e32 v0, s4
+; CHECK-NEXT:    s_setpc_b64 s[30:31]
+  %phys = call i16 asm sideeffect "; def $0", "={s8}"()
+  %virt = call i16 asm sideeffect "; def $0", "=s"()
+  %r = and i16 %phys, %virt
+  ret i16 %r
+}
+
+define i8 @inline_asm_i8_in_v_def() {
+; CHECK-LABEL: inline_asm_i8_in_v_def:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; def v8
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    v_mov_b32_e32 v0, v8
+; CHECK-NEXT:    s_setpc_b64 s[30:31]
+  %phys = call i8 asm sideeffect "; def $0", "={v8}"()
+  ; %virt = call i8 asm sideeffect "; def $0", "=v"()  ; currently fails
+  ; %r = and i8 %phys, %virt
+  ; ret i8 %r
+  ret i8 %phys
+}
+
+; currently broken, v8 should be set to v0 & 0xFF
+define void @inline_asm_i8_in_v_use(i8 %val) {
+; CHECK-LABEL: inline_asm_i8_in_v_use:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; CHECK-NEXT:    v_mov_b32_e32 v8, v0
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; use v8
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    s_setpc_b64 s[30:31]
+  call void asm sideeffect "; use $0", "{v8}"(i8 %val)
+  ; call void asm sideeffect "; use $0", "v"(i8 %val)  ; currently fails
+  ret void
+}
+
+define i8 @inline_asm_i8_in_sphys_def() {
+; CHECK-LABEL: inline_asm_i8_in_sphys_def:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; def s8
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    v_mov_b32_e32 v0, s8
+; CHECK-NEXT:    s_setpc_b64 s[30:31]
+  %phys = call i8 asm sideeffect "; def $0", "={s8}"()
+  ; %virt = call i8 asm sideeffect "; def $0", "=s"()  ; currently fails
+  ; %r = and i8 %phys, %virt
+  ; ret i8 %r
+  ret i8 %phys
+}
+
+
+; Single registers for vector types that fit are fine.
+
+define void @inline_asm_2xi16_in_v_use(<2 x i16> %val) {
+; CHECK-LABEL: inline_asm_2xi16_in_v_use:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; CHECK-NEXT:    v_mov_b32_e32 v8, v0
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; use v8
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; use v0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    s_setpc_b64 s[30:31]
+  call void asm sideeffect "; use $0", "{v8}"(<2 x i16> %val)
+  call void asm sideeffect "; use $0", "v"(<2 x i16> %val)
+  ret void
+}
+
+define <2 x i16> @inline_asm_2xi16_in_v_def() {
+; CHECK-LABEL: inline_asm_2xi16_in_v_def:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; def v8
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; def v0
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    v_and_b32_e32 v0, v8, v0
+; CHECK-NEXT:    s_setpc_b64 s[30:31]
+  %phys = call <2 x i16> asm sideeffect "; def $0", "={v8}"()
+  %virt = call <2 x i16> asm sideeffect "; def $0", "=v"()
+  %r = and <2 x i16> %phys, %virt
+  ret <2 x i16> %r
+}
+
+define <2 x i16> @inline_asm_2xi16_in_s_def() {
+; CHECK-LABEL: inline_asm_2xi16_in_s_def:
+; CHECK:       ; %bb.0:
+; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; def s8
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    ;;#ASMSTART
+; CHECK-NEXT:    ; def s4
+; CHECK-NEXT:    ;;#ASMEND
+; CHECK-NEXT:    s_and_b32 s4, s8, s4
+; CHECK-NEXT:    v_mov_b32_e32 v0, s4
+; CHECK-NEXT:    s_setpc_b64 s[30:31]
+  %phys = call <2 x i16> asm sideeffect "; def $0", "={s8}"()
+  %virt = call <2 x i16> asm sideeffect "; def $0", "=s"()
+  %r = and <2 x i16> %phys, %virt
+  ret <2 x i16> %r
+}