[llvm] a7759d1 - GlobalISel: Fix IRTranslator for constantexpr selects

[Matt Arsenault via llvm-commits]

Author: Matt Arsenault
Date: 2020-05-19T09:52:48-04:00
New Revision: a7759d178508771a5ccec2b02ca3f3bd40af4409

URL: https://github.com/llvm/llvm-project/commit/a7759d178508771a5ccec2b02ca3f3bd40af4409
DIFF: https://github.com/llvm/llvm-project/commit/a7759d178508771a5ccec2b02ca3f3bd40af4409.diff

LOG: GlobalISel: Fix IRTranslator for constantexpr selects

This was assuming a select is always an instruction, which is not
true.

Added: 
    

Modified: 
    llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
    llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-constantexpr.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 18fcec55dcf5..61b7a162ae96 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -1008,10 +1008,11 @@ bool IRTranslator::translateSelect(const User &U,
   ArrayRef<Register> Op0Regs = getOrCreateVRegs(*U.getOperand(1));
   ArrayRef<Register> Op1Regs = getOrCreateVRegs(*U.getOperand(2));
 
-  const SelectInst &SI = cast<SelectInst>(U);
   uint16_t Flags = 0;
-  if (const CmpInst *Cmp = dyn_cast<CmpInst>(SI.getCondition()))
-    Flags = MachineInstr::copyFlagsFromInstruction(*Cmp);
+  if (const SelectInst *SI = dyn_cast<SelectInst>(&U)) {
+    if (const CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition()))
+      Flags = MachineInstr::copyFlagsFromInstruction(*Cmp);
+  }
 
   for (unsigned i = 0; i < ResRegs.size(); ++i) {
     MIRBuilder.buildSelect(ResRegs[i], Tst, Op0Regs[i], Op1Regs[i], Flags);

diff  --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-constantexpr.ll b/llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-constantexpr.ll
index b99ef200ea88..3254fb4c9f2a 100644
--- a/llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-constantexpr.ll
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-constantexpr.ll
@@ -22,3 +22,40 @@ define i32 @test() {
   ; CHECK:   S_SETPC_B64_return [[COPY5]], implicit $vgpr0
   ret i32 bitcast (<1 x i32> <i32 extractelement (<1 x i32> bitcast (i32 zext (i1 icmp eq (i32* @var, i32* inttoptr (i32 -1 to i32*)) to i32) to <1 x i32>), i64 0)> to i32)
 }
+
+ at gint = external addrspace(1) global i8, align 4
+
+; Technically we should be able to fold away the compare to true, but
+; currently constexpr doesn't understand null in non-0 address spaces.
+define amdgpu_kernel void @constantexpr_select_0() {
+  ; CHECK-LABEL: name: constantexpr_select_0
+  ; CHECK: bb.1 (%ir-block.0):
+  ; CHECK:   [[GV:%[0-9]+]]:_(p1) = G_GLOBAL_VALUE @gint
+  ; CHECK:   [[C:%[0-9]+]]:_(p1) = G_CONSTANT i64 0
+  ; CHECK:   [[ICMP:%[0-9]+]]:_(s1) = G_ICMP intpred(eq), [[GV]](p1), [[C]]
+  ; CHECK:   [[C1:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+  ; CHECK:   [[C2:%[0-9]+]]:_(s32) = G_CONSTANT i32 0
+  ; CHECK:   [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[C1]], [[C2]]
+  ; CHECK:   [[DEF:%[0-9]+]]:_(p1) = G_IMPLICIT_DEF
+  ; CHECK:   G_STORE [[SELECT]](s32), [[DEF]](p1) :: (store 4 into `i32 addrspace(1)* undef`, addrspace 1)
+  ; CHECK:   S_ENDPGM 0
+  store i32 select (i1 icmp eq (i8 addrspace(1)* @gint, i8 addrspace(1)* null), i32 1, i32 0), i32 addrspace(1)* undef, align 4
+  ret void
+}
+
+define amdgpu_kernel void @constantexpr_select_1() {
+  ; CHECK-LABEL: name: constantexpr_select_1
+  ; CHECK: bb.1 (%ir-block.0):
+  ; CHECK:   [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 1024
+  ; CHECK:   [[INTTOPTR:%[0-9]+]]:_(p1) = G_INTTOPTR [[C]](s64)
+  ; CHECK:   [[GV:%[0-9]+]]:_(p1) = G_GLOBAL_VALUE @gint
+  ; CHECK:   [[ICMP:%[0-9]+]]:_(s1) = G_ICMP intpred(eq), [[INTTOPTR]](p1), [[GV]]
+  ; CHECK:   [[C1:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
+  ; CHECK:   [[C2:%[0-9]+]]:_(s32) = G_CONSTANT i32 0
+  ; CHECK:   [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[C1]], [[C2]]
+  ; CHECK:   [[DEF:%[0-9]+]]:_(p1) = G_IMPLICIT_DEF
+  ; CHECK:   G_STORE [[SELECT]](s32), [[DEF]](p1) :: (store 4 into `i32 addrspace(1)* undef`, addrspace 1)
+  ; CHECK:   S_ENDPGM 0
+  store i32 select (i1 icmp eq (i8 addrspace(1)* @gint, i8 addrspace(1)* inttoptr (i64 1024 to i8 addrspace(1)*)), i32 1, i32 0), i32 addrspace(1)* undef, align 4
+  ret void
+}