[clang] [DirectX] Fix HLSL bitshifts to leverage the OpenCL pipeline for bitshifting (#55106) (PR #81030)

[Cooper Partin via cfe-commits]

https://github.com/coopp updated https://github.com/llvm/llvm-project/pull/81030

>From eb6c7e6e9d4ccaf6e63714d2d94a518cc00bcc82 Mon Sep 17 00:00:00 2001
From: Cooper Partin <coopp at ntdev.microsoft.com>
Date: Wed, 7 Feb 2024 11:32:56 -0800
Subject: [PATCH 1/2] [DirectX] Fix HLSL bitshifts to leverage the OpenCL
 pipeline for bitshift masking

---
 clang/lib/CodeGen/CGExprScalar.cpp     |  4 +--
 clang/test/CodeGenHLSL/shift-mask.hlsl | 35 ++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 2 deletions(-)
 create mode 100644 clang/test/CodeGenHLSL/shift-mask.hlsl

diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index df8f71cf1d9008..fa03163bbde577 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -4168,7 +4168,7 @@ Value *ScalarExprEmitter::EmitShl(const BinOpInfo &Ops) {
   bool SanitizeBase = SanitizeSignedBase || SanitizeUnsignedBase;
   bool SanitizeExponent = CGF.SanOpts.has(SanitizerKind::ShiftExponent);
   // OpenCL 6.3j: shift values are effectively % word size of LHS.
-  if (CGF.getLangOpts().OpenCL)
+  if (CGF.getLangOpts().OpenCL || CGF.getLangOpts().HLSL)
     RHS = ConstrainShiftValue(Ops.LHS, RHS, "shl.mask");
   else if ((SanitizeBase || SanitizeExponent) &&
            isa<llvm::IntegerType>(Ops.LHS->getType())) {
@@ -4237,7 +4237,7 @@ Value *ScalarExprEmitter::EmitShr(const BinOpInfo &Ops) {
     RHS = Builder.CreateIntCast(RHS, Ops.LHS->getType(), false, "sh_prom");
 
   // OpenCL 6.3j: shift values are effectively % word size of LHS.
-  if (CGF.getLangOpts().OpenCL)
+  if (CGF.getLangOpts().OpenCL || CGF.getLangOpts().HLSL)
     RHS = ConstrainShiftValue(Ops.LHS, RHS, "shr.mask");
   else if (CGF.SanOpts.has(SanitizerKind::ShiftExponent) &&
            isa<llvm::IntegerType>(Ops.LHS->getType())) {
diff --git a/clang/test/CodeGenHLSL/shift-mask.hlsl b/clang/test/CodeGenHLSL/shift-mask.hlsl
new file mode 100644
index 00000000000000..b8a7dced1a0ee5
--- /dev/null
+++ b/clang/test/CodeGenHLSL/shift-mask.hlsl
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
+// RUN:   dxil-pc-shadermodel6.3-library %s \
+// RUN:   -emit-llvm -disable-llvm-passes -o - | FileCheck %s
+
+int shl32(int V, int S) {
+  return V << S;
+}
+
+// CHECK: define noundef i32 @"?shl32{{[@$?.A-Za-z0-9_]+}}"(i32 noundef %V, i32 noundef %S) #0 {
+// CHECK-DAG:  %[[Masked:.*]] = and i32 %{{.*}}, 31
+// CHECK-DAG:  %{{.*}} = shl i32 %{{.*}}, %[[Masked]]
+
+int shr32(int V, int S) {
+  return V >> S;
+}
+
+// CHECK: define noundef i32 @"?shr32{{[@$?.A-Za-z0-9_]+}}"(i32 noundef %V, i32 noundef %S) #0 {
+// CHECK-DAG:  %[[Masked:.*]] = and i32 %{{.*}}, 31
+// CHECK-DAG:  %{{.*}} = ashr i32 %{{.*}}, %[[Masked]]
+
+int64_t shl64(int64_t V, int64_t S) {
+  return V << S;
+}
+
+// CHECK: define noundef i64 @"?shl64{{[@$?.A-Za-z0-9_]+}}"(i64 noundef %V, i64 noundef %S) #0 {
+// CHECK-DAG:  %[[Masked:.*]] = and i64 %{{.*}}, 63
+// CHECK-DAG:  %{{.*}} = shl i64 %{{.*}}, %[[Masked]]
+
+int64_t shr64(int64_t V, int64_t S) {
+  return V >> S;
+}
+
+// CHECK: define noundef i64 @"?shr64{{[@$?.A-Za-z0-9_]+}}"(i64 noundef %V, i64 noundef %S) #0 {
+// CHECK-DAG:  %[[Masked:.*]] = and i64 %{{.*}}, 63
+// CHECK-DAG:  %{{.*}} = ashr i64 %{{.*}}, %[[Masked]]
\ No newline at end of file

>From 10e4cf84afe41cbc5508b914605e0817c5b62509 Mon Sep 17 00:00:00 2001
From: Cooper Partin <coopp at ntdev.microsoft.com>
Date: Thu, 8 Feb 2024 08:59:48 -0800
Subject: [PATCH 2/2] Add newline to end of .hlsl test file

---
 clang/test/CodeGenHLSL/shift-mask.hlsl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/test/CodeGenHLSL/shift-mask.hlsl b/clang/test/CodeGenHLSL/shift-mask.hlsl
index b8a7dced1a0ee5..d046efaf9c1f9c 100644
--- a/clang/test/CodeGenHLSL/shift-mask.hlsl
+++ b/clang/test/CodeGenHLSL/shift-mask.hlsl
@@ -32,4 +32,4 @@ int64_t shr64(int64_t V, int64_t S) {
 
 // CHECK: define noundef i64 @"?shr64{{[@$?.A-Za-z0-9_]+}}"(i64 noundef %V, i64 noundef %S) #0 {
 // CHECK-DAG:  %[[Masked:.*]] = and i64 %{{.*}}, 63
-// CHECK-DAG:  %{{.*}} = ashr i64 %{{.*}}, %[[Masked]]
\ No newline at end of file
+// CHECK-DAG:  %{{.*}} = ashr i64 %{{.*}}, %[[Masked]]